This Program Project Grant is focused on the applications of monoclonal antibodies (mAbs) for therapy of gastrointestinal (GI) cancer. Preclinical studies will focus on anti-idiotype mAb vaccines. The specific objectives of the individual research projects are the following: 1. Generation of anti-idiotype antibodies for GI carcinoma. 2. Determining the avidities of anti- idiotype mAbs, determine the DNA and protein sequences, generate computer models for idiotope determining loops, sequence and synthesize the peptides, as the first step towards clinical trials. 3. Clinical trial for GI cancer with an anti-idiotype mAb (anti- 8019).